I. Field of the Invention
The system and method for providing group communication services relates generally to point-to-multipoint communication systems and more particularly to a method and apparatus for providing group communication services.
II. Description of the Related Art
Point-to-multipoint communication systems have been used for many years to provide communications generally between a central location and multiple users of the system. For example, dispatch systems using Land Mobile Radios (LMRs) have been used in trucks, taxis, buses, and other vehicles in order to communicate scheduling information between a central dispatch center and one or more corresponding fleet vehicles. Communications may be directed at a specific vehicle in the fleet or to all vehicles simultaneously.
Another example of a point-to-multipoint communication system is a wireless push-to-talk system. Such a system allows a group of individuals, each having a wireless telephone, to communicate with other members of the group. Typically, a push-to-talk system relies on a single frequency, or dedicated channel, over which communications are received by the wireless telephones. In most systems, only one member may transmit information to the other members at a time. However, all members can listen to the dedicated broadcast channel to receive communications from the single member who is transmitting. Members desiring to transmit to other members of the system typically send an access request by depressing a push-to-talk button on a respective communication device which allows sole access to the dedicated transmission channel.
Push-to-talk systems are typically used in outdoor settings where a group of geographically diverse people, or simply members, require communications with each other in a “point-to-multipoint” fashion. Examples of push-to-talk system uses include workgroup communications, security communications, construction site communication, and localized military communications. The group of people requiring communications with each other is commonly known as a “net,” each member of the net sometimes referred to as a “net member.”
In a typical push-to-talk system, a dedicated channel, sometimes referred to as a broadcast channel, is used to transmit communications from one member to multiple other members of the net simultaneously. Generally, only one member may transmit voice information to the other member users at any given time. If another member attempts to transmit over the broadcast channel while another member is transmitting, interference between the two competing communications will occur, resulting in non-intelligible communications being received by the other net members.
In order to implement a push-to-talk communication system in a conventional wireless communication system, expensive modifications to the infrastructure are necessary. Presently, there exists today at least one wireless push-to-talk communication system that allows point-to-multipoint communications to take place by undertaking such modifications. An example of such a system has been engineered by Motorola Incorporated of Schaumburg, Ill. and marketed as the Nextel Direct Connect® service, offered by Nextel Communications of Reston, Va.
Besides the cost problem associated with current wireless point-to-multipoint communication systems is that, generally, communications are confined to members operating in relative close proximity to each other using the same communication technology. In other words, the point-to-multipoint communications do not extend from a CDMA communication system, for example, to other communication networks or technologies, such as a GSM communication system, a Public Switched Telephone Network (PSTN), a data network, such as the Internet, or to a satellite communication systems, such as the GlobalStar™ satellite communication system.
These obstacles to providing group communication services are overcome by various embodiments of the system and method for providing group communication services as described herein.